When the girls arrive at camp, or any other time, have everyone right down a favorite wish (make them aware that they may be announced at a later time so don't write anything embarrassing).
Have them write their name on it.
Pick eight or nine of them (or few every night at campfire) to come true. Of course they might be exaggerated, for example, if someone wrote - sing a duet with Billy Joel, have someone dress up like him (maybe put a sign on that person that says Billy Joel), and call that person up to sing a duet with "him".
You will be surprised how many dreams you can make come true (sort of)